Early life experiences appear to have a significant and long-lasting impact on the maturing brain. Experience-dependent plasticity, during the brief, but extreme postnatal epoch of heightened nervous system receptivity commonly referred to as the critical period (Wiesel & Hubel, 1965; Simons & Land, 1987), facilitates stable perceptual biases in the adult cortex (de Villers-Sidani, Chang, Bao, Merzenich, 2007).
Longitudinal studies with infants offer insights into the etiology of Language Learning Impairment (LLI). From birth, infants possess remarkably sophisticated acoustic capabilities allowing the perception of speech as well as non-speech sounds. This phenomenon enables the study of linguistic precursors well before spoken language emerges. Levels of performance on tasks tapping these early precursors (such as rapid auditory processing) have been shown to be predictive of language skills at 16, 24, and 36 months of age.
The mechanism by which lower-level processing skills influence later language outcomes likely occurs early on in development, when acoustic and phonological maps are being constructed. Over time, the cumulative effects of poorly encoded representations may result in delay or impairment of language skills. However, if early intervention were successful in increasing efficiency of early auditory processing, it is possible that later language difficulties could be reduced or eliminated. The progress in this art is hampered due to the fact that the pool of language-related technologies for infants is quite small.
One such example is the Baby Babble-Blanket (BBB), a system developed to provide infants and developmentally delayed children with a mechanism that enables them to communicate or control their environment. When lying on the blanket, the infants use simple movements, such as head rolling or leg raising to activate digitized sounds. The BBB intervention was used to train cause-effect relationships in 5 month olds with limited physical ability, and was found to be successful at increasing switch activations in response to the sound of the mother's voice.
Another project involving infant communication is the Early Vocalization Analyzer (EVA), a program that automatically analyzes digitized recordings of infant vocalizations. The first goal of EVA is to analyze prespeech utterances in a standardized fashion to eliminate errors in human coding. By comparing the prelinguistic utterances of normal and at-risk infants with a variety of etiologies, EVA can also be used to assess and possibly predict later language difficulties. However, EVA is focused primarily on detecting spoken language disorders and does not adequately address the problems associated with identification of children at risk for receptive and expressive language deficits.
Accordingly, there remains a need for new approaches to remediation that can be used with infants. Families with a child diagnosed with a language learning disorder would be very interested in such a technique (interface) that could serve as a corrective or preventative measure for an infant sibling. Infants born into families with a history of language learning impairments are at significantly higher risk for such disorders. The public at large would be interested in an interface device that would support optimal language development.
It is estimated that roughly 20% of preschool- and school-aged children suffer from deficits in language. More than 50% of children exhibiting early impairments specific to language continue on to develop dyslexia, a disorder associated with lifelong difficulties in the literacy domain.
Therefore, there is a need in the art for methods and systems for screening young infants at risk for LLI and treatment of this disorder once it is identified.